Automatic garage doors, gas or electric stoves and ovens and in-home security alarm systems have become common household appliances in many U.S. homes. It is important that an automatic garage door remains closed, that the stoves and ovens remain turned off, and that the security alarms are activated when the household occupant leaves his/her home, usually by driving.
An automatic garage door remaining open is frequently an invitation to theft. In many instance, garage doors are often left open when the occupant leaves due to carelessness on the occupant's part, or the safety device of the automatic door is interrupted by a wandering pet or for other reasons, which causes the door to reopen, unbeknown to the occupant. A forgotten and unsupervised burning stove or oven could cause fire. A de-activated security alarm system could leave the home unprotected. These are the most common items that home occupants forget to check when they leave their homes.
Similar solutions for the garage door problem have been proposed. U.S. Pat. No. 6,011,468 issued to Lee describes a garage door alarm which uses a pair of ultrasonic receivers at the remote garage door opener. In the garage are located two transmitters, one which emits a short distance signal and a second which emits a long distance signal. The transmitters operate only if the garage door remains open. When the vehicle travels beyond the range of the short distance receiver and in the range of long distance receiver, and the garage door is still open, the alarm will activate. However, if the vehicle travels beyond the range of the long distance receiver and the garage door is still open, the alarm will be silent. This invention falls short of solving a real life problem. What will happen if the ultrasonic signal is blocked by the buildings nearby? Will the device still be operative if nearby households have installed the same device? Will the receivers at the remote opener pick up other ultrasonic signals if that neighborhood has a similar device installed? What should be done if the property has multiple cars and multiple garage doors? Will the system still remind the user if the transmitters' power was cut out before the user reaches the short distance threshold? This system fails in these respects because it does not know the last state of the garage door if the transmission is terminated. Interference and interruption do occur in wireless communication, therefore storing the last state of the sensing object and allowing a wait period for certainty are very important.
U.S. Pat. No. 6,634,408 issued to Mays discloses a device which controls the closure of a garage door when a garage door controller located in a vehicle moves out of the range of a transmitter located in the occupant's garage. The effective outcome of this invention is similar to a delay time clock for the automatic closure of the garage door. A device such as time clock for automatic closure is not recommended for household use since there may be children and pets around during the automatic closing of the garage door when no adult is around to supervise.
Therefore, a need exists for a system which can be easily installed in a vehicle and house and which allows the status of one or more appliances to be monitored. If the status of the appliance requires that the household occupant take necessary action, the system will warn the occupant before he travels too far from his/her house. The function of the device shall be for reminding only and not for automatically controlling any of the appliances from a distance. The system would preferably remain operative even though other similar devices are operating in the same area. The system would preferably be a “smart” system that can operate independently of the type of sensor being used. The system would preferably be able to determine the last state of the monitored appliance even though the transmission of the signal is terminated. Also, the system shall comply with all local, state, and federal laws regarding the transmitting of radio frequency signals.
The foregoing reflects the state of the art of which the inventor is aware, and is tendered with a view toward discharging the inventor's acknowledged duty of candor, which may be pertinent to the patentability of the present invention. It is respectfully stipulated, however, that the foregoing discussion does not teach or render obvious, singly or when considered in combination, the inventor's claimed invention.